1. Field of Invention
The field of the currently claimed embodiments of this invention relates to optical coherence tomography (OCT) systems, and more particularly to sapphire lens-based optical fiber probes for OCT systems and OCT systems that incorporate the probes.
2. Discussion of Related Art
Optical coherence tomography (OCT) is being widely used for non-destructive, cross-sectional imaging of biological tissues [1-6]. A single-mode fiber can be lensed with state-of-the-art micro-optics to form an imaging beam with a spot size around a few μm in gastrointestinal endoscopy, coronary artery imaging, and needle-based Doppler OCT. The commonly used lensing components in fiber-optic microprobes are gradient-index (GRIN) lenses [7,], drum lenses [9], fiber fused ball lenses [10], and special liquid-forming ball lenses. For retina vitrectomy surgery, we have been developing a handheld compact forward sensing and imaging probe attached to surgical tool tips to detect the distance between the tool tips and critical areas of the retina, so they can avoid scratching healthy retina surfaces. The GRIN lens-based common-path (CP) probe has only led to sensitivity up to 44 dB in SDOCT. Although fused ball lenses demonstrated impressive performance in non-CP Doppler OCT, several main drawbacks of fused lenses are lower refractive index (n=1.48), teardrop (non-spherical shape), limited diameter (generally less than 500 μm), and they are fragile—which prevents the imaging lens from being directly exposed to tissue. There thus remains a need for improved probes for OCT systems, and OCT systems that incorporate the probes.